Researchers at the Ecole Polytechnique Federale de Lausanne have discovered that proximity to insulating materials can significantly reduce the performance of nanoresonators. Published on July 7, 2026, in Nature Physics, this study reveals that even without physical contact, nearby dielectrics can introduce energy loss, impacting their applications in sensitive detection and quantum technologies.
Understanding Nanoresonators and Their Applications
Nanoresonators are tiny vibrating structures that oscillate at frequencies ranging from a few kilohertz to gigahertz. They are essential components in various applications, including:
- Ultrasensitive detectors for mass and force
- Temperature and pressure measurement devices
- Radio frequency filters
- On-chip clocks
These advanced devices are also being used to create quantum states of macroscopic objects and test fundamental physics principles.
The Role of Proximity in Energy Loss
The research led by Tobias J. Kippenberg has shown that bringing these resonators close to insulating materials, such as silicon dioxide or silicon nitride, can lead to additional energy loss. The primary mechanism behind this phenomenon is the presence of static electric charges that can become trapped in the resonator.
As the resonator vibrates, it generates a changing electric field in its surroundings. If nearby materials exhibit small electrical losses, this field can cause energy to dissipate, leading to a reduction in the quality factor of the resonator. This effect is termed noncontact friction, a phenomenon previously documented in atomic force microscopy.
Experimental Findings and Implications
The scientists constructed a model that predicted a clear signature: lower-frequency vibrations should experience greater energy loss. They validated this by suspending silicon nitride strings approximately 500 nanometers above a dielectric layer and observing the decay rates of different vibration modes. The results confirmed that the lowest-frequency modes exhibited extra energy loss, aligning with their predictions.
In a subsequent experiment, the researchers designed strings with a high Q factor and placed them between photonic crystal cavities with very narrow gaps. They found that as the gap size decreased, the quality factor dropped significantly—by up to a factor of 10 in some instances. These findings highlight the need for new design constraints in ultracoherent nanomechanical systems, emphasizing the importance of accounting for noncontact friction due to trapped charges.
Understanding these hidden sources of energy loss can also be beneficial. Researchers can leverage this mechanism to probe dielectric losses in thin films or enable controlled coupling to other electric systems. As resonators continue to advance in sensing and quantum technologies, managing these energy losses will be crucial for optimizing their performance.
🤖 This article was rewritten by Feed and Figures' editorial AI from a report originally published by Phys.org. Facts and quotes are preserved from the original; the rewrite focuses on clarity and structure. For the unedited original, see the source link below.
